What happens if my friend overstays her visa in Thailand by one day?

Hi guys- some advice for thailand please! Has anyone overstayed a visa by 1 or less days? My friends current visa finishes on 30/07 and she needs to travel to laos for a new one. The flight from CM to UT in currently 1800 tbh and 30th but on the 1st its only 600 tbh. I looked online for her and on the thai embassy website it says usually you wont get fined for overstaying a day. She is low on money and wanted to know if anyone had any troubles in overstaying for half a day. I think what she is mostly concerned about is getting back in.. She is going to Laos to get an ED visa. Shes worried it might affect that. **And i am asking for a friend, she is russian and speaks limited english so please if you feel like attacking me for this question please just dont bother :) thank you for your help.